Comparision of <sup>11</sup>C-methionine and <sup>11</sup>C-choline pet/ct for parathyroid visualization: a prospective study

INTRODUCTION: Primary hyperparathyroidism (PHPT) is a common endocrine disorder. Minimal invasive parathyroidectomy (PTX) is favorable surgical approach in PHPT treatment. Its success is highly dependent on accurate preoperative localization of all causative parathyroid adenomas. Despite the fact that wide range of visualization methods are applied in PHPT diagnostics, PHPT persistence occurs. Therefore, the search for additional visualizing tools of parathyroid adenomas remains relevant. Recently, positron emission tomography/computed tomography (PET/CT) has been used in order to improve PHPT diagnostics. OBJECTIVE: To evaluate the diagnostic effectiveness of PET/CT with 11 C-methionine and 11 C-choline in patients with PHPT based on the intensity of both tracers uptake in parathyroid adenomas. MATERIALS AND METHODS: The data of 26 patients diagnosed with PHPT was analyzed. PET/CT with 11 C-choline was performed in 14 patients, with 11 C-methionine — in 10 patients, with two radiopharmaceuticals — in two patients. All patients underwent PTX. Histological examination’s results were compared with the results of PET/CT. Using the software, the standardized uptake value of radiopharmaceuticals in histologically verified parathyroid adenomas/hyperplasias and in the trapezius muscle was obtained, then tumor-to-background ratios (TBR) of 11 C-methionine and 11 C-choline were calculated.Statistics: Software STATISTICA 10 was used in statistical analysis.RESULTS: 11 C-choline TBR median was of 2.3 (1.6; 3.2), median of 11 C-methionine TBR showed slightly higher values — 2.5 (1.9; 3,6). However, no significant difference was found between the two radiopharmaceuticals’ uptake in parathyroid adenomas.DISCUSSION: The scientific impact of current study is determined by the diagnostic effectiveness comparison between PET/CT with 11 C-methionine and 11 C-choline, which is based on the accumulation intensity of both radiopharmaceuticals in parathyroid adenomas.CONCLUSION: The intensity of accumulation of 11 C-methionine and 11 C-choline by hyperfunctioning parathyroid tissue does not differ significantly. Thus both tracers might be successfully applied for topic diagnosis of parathyroid adenomas in patients with PHPT.